Novel polycationic biocides: Synthesis and antibacterial activity of polymeric phosphonium salts

Various polymeric phosphonium salts and the corresponding low-molecular-weight model compounds were prepared and their antibacterial activities against Staphylococcus aureus and Escherichia coli were explored by the viable cell counting method in sterile distilled water. Antibacterial activity of the polymers was found to be higher than that of the corresponding model compounds, particularly against S. aureus. Furthermore, the polymeric phosphonium salt exhibited a higher activity by 2 orders of magnitude than the polymeric quaternary ammonium salt with the same structure except the cationic part. Compounds with the longest alkyl chain (octyl) studied were found to exhibit particularly high activity, and this finding may be ascribed to the contribution of the increased hydrophobicity of the compounds to the cidal activity. © 1993 John Wiley & Sons, Inc.     

Catalytic Sandmeyer cyanation as a synthetic pathway to aryl nitriles

Aryl nitriles ArCN were obtained by the Cu(I)/Cu(II) catalysed reaction of aryl diazonium salts with KCN in good yields.     

Thermal decomposition of rare earth element enanthates

The conditions of formation of Y, La and lanthanide (from Ce(III) to Lu) enanthates were worked out, their composition and their solubilities in water at 291 K were determined, and the conditions of their thermal decomposition were studied. They were prepared as crystalline solids with general formula Ln(C₇H₁₃O₂)₃·nH₂O, wheren=2–10. On heating, they decompose in two or three steps. They first lose some water molecules and then decompose to the oxides directly (salts of Y and heavy lanthanides) or via the intermediate formation of Ln₂O₂CO₃ (salts of La, Pr, Nd, Sm and Eu). Only yttrium enanthate dihydrate loses 2 water molecules on heating to form an anhydrous complex, which decomposes directly to Y₂O₃. The temperatures of dehydration are similar for all complexes (323–343 K), while the temperatures of oxide formation vary irregularly from 823 K for CeO₂ to 1078 K for La₂O₃.     

Thermodynamic simulation of four-component carnallite type systems

Summary The standard method ofPitzer for predicting the solubility isotherms of systems in which solid phases with a constant composition crystallize is applied to cases when mixed crystals are formed. The four-component carnallite type systems RbCl-CsCl-MgCl₂-H₂O, RbCl-KCl-MgCl₂-H₂O, and RbCl-RbBr-MgCl₂-MgBr₂-H₂O and the corresponding subsystems are thermodynamically simulated at 25°C. It is established that the solubility diagrams consist of crystallization regions of the simple saltsMX,MX, MgX ₂·6H₂O, and MgX₂·6H₂O and of the corresponding carnallite type double salts with the composition 1:1:6. A method of calculation of the integralGibbs energy of mixingG ^mix(s) of crystals formed in water-salt systems has been proposed. The results on the systems RbCl-KCl-H₂O, RbCl-RbBr-H₂O, and MgCl₂-MgBr₂-H₂O are compared with experimental data from the literature and with values calculated using various models.

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Thermodynamische Simulation von Vierkomponentensystemen des Carnallit-Types

Zusammenfassung DiePitzer-Methode zur Voraussage der Löslichkeitsisothermen in Mehrstoffsystemen, in welchen feste Phasen mit konstanter Zusammensetzung auskristallisieren, wurde auch für Fälle angewendet, bei denen sich Mischkristalle bilden. Die Vierstoffsysteme RbCl-CsCl-MgCl₂-H₂O, RbCl-KCl-MgCl₂-H₂O und RbCl-RbBr-MgCl₂-MgBr₂-H₂O, aus welchen Carnallit-Typ-Mischkristalle auskristallisieren, und die dazugehörigen Dreistoff-Randsysteme wurden bei 25°C simuliert. Man stellt fest, daß die Löslichkeitsdiagramme sowohl Kristallisationsbereiche der einfachen SalzeMX,M'X, MgX ₂·6H₂O und MgX ₂·6H₂O als auch der entsprechenden carnallitartigen Doppelsalze mit der Zuzammensetzung 1:1:6 umfassen. Eine Methode zur Berechnung derGibbs-EnergieG ^mix(s) für die in Wasser-Salz-Systemen gebildeten Mischkristalle wird vorgeschlagen. Die für die Systeme RbCl-KCl-H₂O, RbCl-RbBr-H₂O und MgCl₂-MgBr₂-H₂O erhaltenen Ergebnisse werden mit experimentellen Literaturdaten und Resultaten von Berechnungen aufgrund verschiedener Modelle verglichen.

     

氯化钪-氯化钠-氯化钾熔盐制备新工艺研究

研究了以Sc2O3为原料，盐酸回流溶解后与NaCl，KCl，NH4Cl溶液混合，经蒸发浓缩、结晶、真空预脱水，再在氩气保护下分段升温脱水、升华除去过量NI-hCl后制备ScCl3-NaCl-KCl熔盐的新工艺。研究表明，添加NH4Cl后加热脱水时，NH4Cl分解产生的HCl气体能抑制ScCl3水合物加热过程中的水解，溶解产生的水不溶性钪，从而有效地防止了Sc2O3等水不溶化合物的生成。制备的ScCl3-NaCl-KCl熔盐脱水完全、水不溶性钪含量很低，能满足熔盐金属热还原法制备金属钪及铝钪中间合金对熔盐原料的要求。     

Effect of the Structure of the Acyl Group on the Kinetics of Exchange between O-Nucleophiles

We have studied the rate of 15 reactions of acyl transfer from O-acyl salts of 4-dimethylaminostyryl-4-pyridine N-oxide to 4-morpholinopyridine and 4-dimethylaminopyridine N-oxides in acetonitrile solutions. Analysis of the results based on the Shaik – Pross approach and the Marcus equation shows that if the structure of the acyl group is varied, then the reactivity is determined by such parameters as the resonance interaction in the transition state (B) or the internal barrier (G ₀) of the reaction.     

Chemical reactivity of [1,2,3]triazolo[1,5-a]- and [1,5-c]-pyrimidinium salts

The chemical reactivity of the [1,2,3]triazolo[1,5-a]- and [1,5-c]-pyrimidinium salts towards morpholine, water and sodium methoxide have been studied. Among others, new 1-aza and 2-azabutadienes substituted by a [1,2,3]-triazole ring were obtained in the course of the opening of the positively charged pyrimidine ring.     

2-氨基-4, 6-二甲基嘧啶与锌盐配合物的制备及生成焓测定

Thepyrimidinesasaclassareknowntopossessextraordinarybiologicalpropertiesthataregenerallydistinguishedqualitativelybytheirapplicationsinpesticide,herbicide,bactericide,andmedicineinter-mediates犤1犦.Asurveyoftheseapplicationsandanum-beroftherelatedvariationsthataredevelopedrecent-ly,suchastheextraordinaryeffectiveherbicideofsulfonylsulfourea,revealsthebroadbiologicalimpor-tancejustbecauseofthewideoccurrenceofpyrimi-dinesringsystemsinthesemolecules犤2犦.Ithasbeenshownthatthemedicineintermediates…     

Synthesis of 4-arylcarbamoyl-5-(2-hydroxynaphthylazo)imidazoles and 1-substituted naphtho[2,1-e]imidazo[5,1-c][1,2,4]triazines

The reactions of β-naphthol with 5-diazoimidazoles and imidazolyl-5-diazonium salts containing chemically different carboxamide groups in position 4 were studied. Heterocyclization of 4-arylcarbamoyl-5-(2-hydroxynaphthylazo)imidazoles formed in these reactions was investigated. The presence of the NH fragment in the amide group prevents this process, the reaction giving instead 3-substituted 3,7-dihydroimidazo[4,5-d][1,2,3]triazin-4-ones, which is due to reversibility of C-azo coupling. Methods for modification of 1-ethoxycarbonyl group in the naphtho[2,1-e]imidazo[5,1-c][1,2,4]triazine system were developed and used to prepare substituted carboxamides inaccessible by other routes. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1208–1213, July, 2006.     

Polarography in solution of some problems in organic chemistry: recent applications

Applications of chromatographic and atomic absorption methods are compared with those of electroanalytical techniques. The limitations of electroanalytical procedures and their advantages, such as speed, sensitivity and speciation are discussed. Among applications of polarography and voltammetry to a solution of basic problems, attention has been paid to the possibility to distinguish the degree of conjugation (e.g. of compounds containing the grouping CNNC), to a contribution to understanding of solution chemistry of mitomycin C and to processes involved in the reduction of cephalosporins. Among practical applications, the possibility to analyze suspensions, which can be carried out without separation offers advantages. Examples are interactions in suspensions of bile salts in the presence of metal (II) ions, adsorptions of various pesticides and other toxic materials on lignin and the possibility to follow alkaline cleavage of lignin in buffers pH 8-12 at 25 °C. Most of these studies would not be possible to carry out using other techniques.